Study of Rh/Ce_0.75Zr_0.25O_{2 – δ}/θ-Al₂O₃/FeCrAl Catalyst Regeneration after Diesel Fuel Autothermal Reforming

Abstract

A study of soot (coke) formation on the surface of a structured Rh/Ce0.75Zr0.25O2/Al2O3/FeCrAl catalyst during autothermal reforming of diesel fuel into synthesis gas was performed. The SEM studies revealed the formation of fibrous carbon particles of 5–50 µm in size on the catalyst surface. It was found that the process of coke formation occurs on the catalytic coating surface, causes no exfoliation and/or damage of the catalytic layer, and the carbon deposits are readily oxidized during catalyst regeneration by oxygen or water vapor. Intensive oxidation of soot with oxygen begins at a temperature of 450°C; a major part of carbon deposits is oxidized even before the reactor furnace reaches the operating temperature of diesel fuel autothermal reforming (750°C). Water vapor oxidizes carbon deposits as well, but less efficiently than oxygen. The catalyst regeneration with water vapor proceeds actively at a temperature of 750°C that proves the possibility of catalyst self-regeneration in the process of diesel fuel autothermal reforming, which is performed with water excess.